Gallas is struggling with an eye injury that he suffered during the Champions League victory over Standard Liege on Tuesday night.
The former Chelsea star is also struggling with an ankle problem.
“There is a big question mark about him at the moment,” said Wenger. “I cannot say that William Gallas will play, unfortunately. The ankle should be alright but the eye is still very swollen.
“He wears contact lenses and at the moment he would not get them in. We hope on Sunday it will be better. He is not comfortable but I am optimistic because we still have three days.”
